1. Field of the Invention
The present invention generally relates to an intraluminal catheter device for use in angioplasty and delivery of a therapeutic agent. Particularly, the present invention is directed to a catheter having an expandable member formed of a matrix of fiber elements and suitable for insertion into the vascular system for delivering a therapeutic agent.
2. Description of Related Art
The systemic administration of therapeutic agents, such as by transoral or intravenous means, treats the body as a whole even though the disease to be treated may be localized. In some cases, systemic administration may not be desirable because the therapeutic agents may have unwanted effects on parts of the body which are not to be treated, or because treatment of the diseased part of the body requires a high concentration of a therapeutic agent that may not be achievable by systemic administration.
It is therefore often desirable to administer therapeutic agents at localized sites within the body. Common examples include cases of localized vascular disease (e.g., heart disease) or diseased body lumens. Among the treatments becoming available for local treatment of vascular disease, are drug-eluting balloons. This type of medical device is typically a percutaneous transluminal coronary angioplasty (PTCA) balloon catheter that carries a therapeutic agent on the surface of the balloon for delivery to the vessel wall. The method generally includes the steps of adding a therapeutic agent to the balloon surface using any of a number of manufacturing processes, such as dip coating, spray coating, painting or pipetting onto the balloon, electron ion deposition, or plasma gamma discharge deposition, inserting the catheter into a blood vessel to a desired location, and expanding the catheter balloon against the surrounding tissue to allow the release of the drug.
In these cases, the therapeutic agent disposed on the balloon surface is exposed to the surrounding environment. As a result, it may contact the vascular surface as the device is tracked through the vessel to the treatment site, resulting in loss of the therapeutic agent and a reduced dose of the therapeutic agent to the target site. A further drawback is the premature diffusion of the drug during delivery into the body.
In view of the potential drawbacks to conventional drug delivery techniques, there exists a need for a device and method for the controlled, localized delivery of therapeutic agents to target locations or lesions within a mammalian body, while preventing the premature release or removal of the therapeutic agent during delivery.